The Dijet Mass Spectrum and Angular Distributions with the DØ Detector
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Published: 1996
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Published: 1996
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Published: 1996
Total Pages: 22
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DOWNLOAD EBOOKWe present preliminary results from an analysis of dijet data collected during the 1994-95 Tevatron Collider run with an integrated luminosity of 91 pb−1. Measurements of dijet mass spectra and dijet angular distributions in {anti p}p collisions at (square root)s- = 1.8 TeV are compared with next-to-leading order QCD theory.
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Published: 1991
Total Pages: 4
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DOWNLOAD EBOOKThe dijet mass and the jijet angular distribution, as measured in the CDF detector at the Fermilab Tevatron Collider, are compared to leading order (LO) and next-to-leading (NLO) order QCD calculations. 5 refs., 1 fig., 1 tab.
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Published: 1996
Total Pages: 4
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DOWNLOAD EBOOKThe authors present preliminary results from an analysis of dijet data collected during the 1994--1995 Tevatron Collider run with an integrated luminosity of 91 pb−1. Measurements of dijet mass spectrum distributions in {anti p}p collisions at (square root)s = 1.8 TeV are compared with next-to-leading order QCD theory.
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Published: 2016
Total Pages: 21
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DOWNLOAD EBOOKThis Letter describes a model-agnostic search for pairs of jets (dijets) produced by resonant and non-resonant phenomena beyond the Standard Model in 3.6 fb-1 of proton–proton collisions with a centre-of-mass energy of √s = 13 TeV recorded by the ATLAS detector at the Large Hadron Collider. The distribution of the invariant mass of the two leading jets is examined for local excesses above a data-derived estimate of the smoothly falling prediction of the Standard Model. The data are also compared to a Monte Carlo simulation of Standard Model angular distributions derived from the rapidity of the two jets. No evidence of anomalous phenomena is observed in the data, which are used to exclude, at 95% CL, quantum black holes with threshold masses below 8.3 TeV, 8.1 TeV, or 5.1 TeV5.1 TeV in three different benchmark scenarios; resonance masses below 5.2 TeV for excited quarks, 2.6 TeV in a W' model, a range of masses starting from mZ' = 1.5 TeV and couplings from gq = 0.2 in a Z' model; and contact interactions with a compositeness scale below 12.0 TeV and 17.5 TeV respectively for destructive and constructive interference between the new interaction and QCD processes. These results significantly extend the ATLAS limits obtained from 8 TeV data. As a result, gaussian-shaped contributions to the mass distribution are also excluded if the effective cross-section exceeds values ranging from approximately 50–300 fb for masses below 2 TeV to 2–20 fb for masses above 4 TeV.
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Published: 2016
Total Pages: 21
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DOWNLOAD EBOOKThis Letter describes a model-agnostic search for pairs of jets (dijets) produced by resonant and non-resonant phenomena beyond the Standard Model in 3.6 fb-1 of proton-proton collisions with a centre-of-mass energy of √s = 13 TeV recorded by the ATLAS detector at the Large Hadron Collider. The distribution of the invariant mass of the two leading jets is examined for local excesses above a data-derived estimate of the smoothly falling prediction of the Standard Model. The data are also compared to a Monte Carlo simulation of Standard Model angular distributions derived from the rapidity of the two jets. No evidence of anomalous phenomena is observed in the data, which are used to exclude, at 95% CL, quantum black holes with threshold masses below 8.3 TeV, 8.1 TeV, or 5.1 TeV5.1 TeV in three different benchmark scenarios; resonance masses below 5.2 TeV for excited quarks, 2.6 TeV in a W' model, a range of masses starting from mZ' = 1.5 TeV and couplings from gq = 0.2 in a Z' model; and contact interactions with a compositeness scale below 12.0 TeV and 17.5 TeV respectively for destructive and constructive interference between the new interaction and QCD processes. These results significantly extend the ATLAS limits obtained from 8 TeV data. As a result, gaussian-shaped contributions to the mass distribution are also excluded if the effective cross-section exceeds values ranging from approximately 50-300 fb for masses below 2 TeV to 2-20 fb for masses above 4 TeV.
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Published: 2009
Total Pages: 7
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DOWNLOAD EBOOKWe present the first measurement of dijet angular distributions in p{bar p} collisions at (square root)s = 1.96 TeV at the Fermilab Tevatron Collider. The measurement is based on a dataset corresponding to an integrated luminosity of 0.7 fb−1 collected with the D0 detector. Dijet angular distributions have been measured over a range of dijet masses, from 0.25 TeV to above 1.1 TeV. The data are in good agreement with the predictions of perturbative QCD and are used to constrain new physics models including quark compositeness, large extra dimensions, and TeV−1 scale extra dimensions. For all models considered, we set the most stringent direct limits to date.
Author: Lene Kristian Bryngemark
Publisher: Springer
Published: 2017-12-29
Total Pages: 177
ISBN-13: 3319673467
DOWNLOAD EBOOKThis thesis describes the use of the angular distributions of the most energetic dijets in data recorded by the ATLAS experiment, at CERN’s Large Hadron Collider (LHC), the goal of which is to search for phenomena beyond what the current theory of Particle Physics (the Standard Model) can describe. It also describes the deployment of the method used in ATLAS to correct for the distortions in jet energy measurements caused by additional proton–proton interactions. The thesis provides a detailed introduction to understanding jets and dijet searches at the LHC. The experiments were carried out at two record collider centre-of-mass energies (8 and 13 TeV), probing smaller distances than ever before. Across a broad momentum transfer range, the proton constituents (quarks and gluons) display the same kinematical behaviour, and thus still appear to be point-like. Data are compared to predictions corrected for next-to-leading order quantum chromodynamics (NLO QCD) as well as electroweak effects, demonstrating excellent agreement. The results are subsequently used to set limits on parameters of suggested theoretical extensions to the Standard Model (SM), including the effective coupling and mass of a Dark Matter mediator.
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Published: 2013
Total Pages: 161
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DOWNLOAD EBOOKAuthor: Lydia Audrey Beresford
Publisher: Springer
Published: 2018-09-04
Total Pages: 175
ISBN-13: 331997520X
DOWNLOAD EBOOKThis book addresses one of the most intriguing mysteries of our universe: the nature of dark matter. The results presented here mark a significant and substantial contribution to the search for new physics, in particular for new particles that couple to dark matter. The first analysis presented is a search for heavy new particles that decay into pairs of hadronic jets (dijets). This pioneering analysis explores unprecedented dijet invariant masses, reaching nearly 7 TeV, and sets constraints on several important new physics models. The two subsequent analyses focus on the difficult low dijet mass region, down to 200 GeV, and employ a novel technique to efficiently gather low-mass dijet events. The results of these analyses transcend the long-standing constraints on dark matter mediator particles set by several existing experiments.